This file includes variable descriptions for the datasets that accompany: 
Beck, W.S. and E.K. Hall (2018). Confounding Factors in Algal Phosphorus Limitation Experiments. 

Contact: whitney.beck@colostate.edu

All data was analyzed in R version 3.5.0

Dataset: BeckHall_2018_Expts_AgarpH.csv

Trt = Unique treatment identifier
Cation = Potassium (K) or Sodium (S) in the phosphate salt 
Hydrogen = Monobasic phosphate salt (Two) or dibasic salt (One)
Heat = Phosphate and agar heated together (Heat) vs. separately (NH) 
Conc = Low (0.05 Molar) vs. High (0.5 Molar)
Temp = agar temperature
pH = pH measurement using litmus test strips 


Dataset: BeckHall_2018_Expts_DIpH.csv

Trt = Unique treatment identifier
Cation = K (Potassium) or S (Sodium) in the phosphate salt
Hydrogen = Monobasic phosphate salt (Two) or dibasic salt (One)
Heat = Phosphate and agar heated together (Heat) vs. separately (NH) 
pH_T0 = Starting pH of distilled water
Cond_T0 = Starting conductivity of distilled water
pH_24hr = pH of water after nutrient diffusing substrate vial was incubated for 24 hours
Cond_24hr = pH of water after nutrient diffusing substrate vial was incubated for 24 hours
pH_Change = Difference in starting and ending pH
Cond_Change = Difference in starting and ending conductivity 

Dataset: BeckHall_2018_Expts_RawData.csv

Site = Stream name
Trt = Unique treatment identifier
Cation = K (Potassium), S (Sodium), or NoCat (Control)
Hydrogen = A (One Hydrogen, Dibasic), B (Two Hydrogens, Monobasic), or NoH (Control)
Heat = H (phosphate and agar heated together), NH (phosphate and agar heated separately), or NoCtrl (control) 
Conc = 0.05 M of P added, 0.1 M of P added, 0.5 M of P added, or Control (no phosphate added) 
Expt = A (first experiment), B (second experiment), or C (third experiment)
EtOH Vol (L) = volume in L of buffered ethanol used to extract chlorophyll a
Fb = Fluorometer reading for chlorophyll a before acidification
Fa = Flourometer reading for chlorophyll a after acidification
Fb-Fa = Difference of flourescence units before and after acidification
Area = Area in cm^2 of nutrient diffusing substrate discs
R = Fluorometer correction factor from linear regression with chlorophyll a standards
Chla = Chlorophyll a in ug/cm^2
Resp = Respiration in ug O2/ cm^2/ hr
GPP = Gross primary production in ug O2/ cm^2/ hr
AFDM = Ash-free dry mass in ug/cm^2
AI = autotrophic index (ratio of AFDM/Chla)
GPP/Chla = biomass-specific primary production (ratio of GPP/Chla) 

Dataset: BeckHall_2018_Expts_LogResponseRatios.csv

Same variable descriptions as BeckHall_2018_Expts_RawData.csv except Chla, AFDM, AI, Resp, GPP, and GPP/Chla 
are reported as log response ratios: ln (raw value/ control mean value for the experiment)

Dataset: BeckHall_2018_OverallMetaAnalysis_NData.csv (Data from Beck et al. 2017 Freshwater Biology meta-analysis) 

Site = Site where nutrient diffusing substrate experiment was completed
N_LRR = Effect of nitrogen additions on chlorophyll a: ln(nitrogen chlorophyll a mean/ control chlorophyll a mean)
N_Var = Variance of the log response ratio 
 
Dataset: BeckHall_2018_OverallMetaAnalysis_PData.csv (Data from Beck et al. 2017 meta-analysis) 

Site = Site where nutrient diffusing substrate experiment was completed
P_LRR = Effect of phosphorus additions on chlorophyll a: ln(phosphorus chlorophyll a mean/ control chlorophyll a mean)
P_Var = Variance of the log response ratio 

Dataset: BeckHall_2018_OverallMetaAnalysis_NPData.csv (Data from Beck et al. 2017 meta-analysis) 

Site = Site where nutrient diffusing substrate experiment was completed
NP_LRR = Effect of nitrogen+phosphorus additions on chlorophyll a: ln(nitrogen+phosphorus chlorophyll a  mean/ control chlorophyll a mean)
NP_Var = Variance of the log response ratio 

Dataset: BeckHall_2018_MicrobeMetaAnalysis_LogResponseRatios.csv

Study = Reference of study
Site = Site where nutrient diffusing substrate experiment was completed
Treatment = Nutrient addition treatment: nitrogen (N), phosphorus (P), or nitrogen+phosphorus (NP)
Chla_LRR = Log response ratio for chlorophyll a: ln(treatment chlorophyll a mean/ control chlorophyll a mean)
Chla_LRR_Var = Variance of the log response ratio
AFDM_LRR = Log response ratio for ash-free dry mass: ln(treatment ash-free dry mass mean/ control ash-free dry mass mean)
AFDM_LRR_Var = Variance of the log response ratio
AI_LRR = Log response ratio for autotrophic index: ln(treatment autotrophic index mean/ control autotrophic index mean)
AI_LRR_Var = Variance of the log response ratio 

Dataset: BeckHall_2018_GrazerMetaAnalysis_RawData.csv

Study = Reference study
Site = Site where nutrient diffusing substrate experiment was completed
Grazer = type of grazer manipulated
Trt = Grazed (grazed) vs. ungrazed (none) plots where experiments were deployed
Control Reps = number of replicates for the no-nutrient treatments
Control Mean = mean chlorophyll a for the no-nutrient treatments
Control SE = standard error of chlorophyll a on the no-nutrient treatments
Ctrl SD = standard deviation of chlorophyll a on the no=nutrient treatments
N Reps = number of replicates for the nitrogen treatments
N Mean = mean chlorophyll a for the nitrogen treatments
N SE = standard error of chlorophyll a on the nitrogen treatments
N SD = standard deviation of chlorophyll a on the nitrogen treatments
N LRR = Effect of nitrogen additions on chlorophyll a: ln(nitrogen chlorophyll a mean/ control chlorophyll a mean)
N Var = Variance of the log response ratio 
P Reps = number of replicates for the phosphorus treatments
P Mean = mean chlorophyll a for the phosphorus treatments
P SE = standard error of chlorophyll a on the phosphorus treatments
P SD = standard deviation of chlorophyll a on the phosphorus treatments
P LRR = Effect of phosphorus additions on chlorophyll a: ln(phosphorus chlorophyll a mean/ control chlorophyll a mean)
P Var = Variance of the log response ratio 
NP Reps = number of replicates for the nitrogen+phosphorus treatments
NP Mean = mean chlorophyll a for the nitrogen+phosphorus treatments
NP SE = standard error of chlorophyll a on the nitorgen+phosphorus treatments
NP SD = standard deviation of chlorophyll a on the nitrogen+phosphorus treatments
NP LRR = Effect of nitrogen+phosphorus additions on chlorophyll a: ln(nitrogen+phosphorus chlorophyll a  mean/ control chlorophyll a mean)
NP Var = Variance of the log response ratio 


Dataset: BeckHall_2018_GrazerMetaAnalysis_LogResponseRatios.csv

Study = Reference of study
Grazing = Grazed vs. ungrazed plots where nutrient diffusing substrates were deployed
LRR = Log response ratio for chlorophyll a: ln(treatment chlorophyll a mean/ control chlorophyll a mean)
LRR_Var = Variance of the log response ratio
Trt = Nutrient addition treatment: nitrogen (N), phosphorus (P), or nitrogen + phosphorus (NP)
